Holders for workpieces



July 31, 3956 w. SALZMANN 2,756,550

HOLDERS FOR WORKPIECES Filed Aug. 14, 1953 IflVfTZtOI"! WL'ZAB 2m Jazz-77721111 United States Patent 'ice signor to Wurttembergische Metallwarenfabrik, Geislingen (Steige), Germany Application August 14, 1953, Serial No. 374,273

Claims priority, application Germany August 26, 1952 4 Claims. (Cl. 51-218) This invention relates to apparatus for mounting kni-fe blades or similar work-pieces for treatment such as grinding or poli'shing.

According to Patent No. 2,664,676, dated January 5, 1954 a mass of grinding, polishing or other treating material in a loose condition, preferably in powder, grain or pulp form, is set in rotation in a centrifuge drum which is rotatable about its central axis, and under the action of centrifugal force is formed into a ring of material which however retains its loose nature. The work-piece to be treated is dipped at least partly into this ring. The grinding or polishing material, which is rotating and is maintained under pressure by the centrifugal force, is thereby applied to the surfaces of the work-piece to be treated and moves along these surfaces, thereby efiecting the desired treatment of the surfaces. The work-piece must'be secured to a holder, which is advantageously an arm which can be swung inwards and outwards from the edge of the drum.

In the case of work-pieces such as knife-blades, spoons or the like, definite surfaces, in particular the front and rear faces, must be fully treated, i. e., the whole of the surface must be subjected to the mass of treating material. At the same time care must be taken to ensure that these work pieces are mounted quite firmly and securely.

Previously, the work-pieces have generally been held fixed at two or more points by claw-like or similar holders, which however cover the parts of surfaces which they engage or screen these parts so as to form what may be termed shadows on the surfaces. The work-piece must therefore be unfastened after the first working operation and engaged at other points, in order that the parts of the surfaces left untreated may be treated in a subsequent operation. This procedure is troublesome and time-wasting, and moreover it is inevitable that the subsequently treated parts stand up from the finished surface.

In contrast, the holder according to the present invention consists essentially of an abutment which is capa'ble of supporting at lea-st the forward end of a knifeblade or the like, the abutment surface having a convexity corresponding to a resiliently deformed-shape of the work-piece, and having at its rear end a tool serving to hold the tang or shank of the work-piece, operation of the tool causing the work-piece to be pressed, with resilient deformation, against the concave abutment surface. The work-piece is thereby given .a strain which suflices to hold it securely agains t the abutment surface, without it having to be additionally supported at its forward end. The whole of the surface to be treated remains free and can be ground or polished by the rotating ring of treating material in :a single operation. This results in a considerable saving in time and cost.

The tool which serves for holding the tang or shank and for resiliently deforming the knife blade or other work-piece can be constructed in various ways. For example, an adjustable holding member may be employed into which the tang of a knife blade is inserted and if 2,756,550 Patented July 31, 1956' 2 desired firmly secured, the knife'blade being undistorted, the holding member then being turned, swung or displaced in such manner that the blade is resiliently deformed and applies itself accurately to the correspondingly shaped tl'liil ti'rie'fit surface.

In accordance with a particularly advantageous form of the invention however the means for mounting the tang of a knife blade and for resiliently deforming the blade are combined, in such manner that the mounting of the tang takes place at the same time as the deformation of the whole blade and the pressing thereof against the concave abutment. This can easily be efi'ec'ted with the aid of an eccentric, which rotatably mounted at the rear end of the abutment, and which when actuated presses the tang against a support in such manner that the tang is securely held and at the same time a lever action is exerted on the whole knife blade, so that the blade is resiliently deformed and applied to :the concave abutment surface. After treatment of the exposed surface of the blade in the centrifuged stream of treating medium, the blade holder is swung out of the centrifuge drum and the blade is turned over so that the other surface can be likewise treated.

A practical form of the invention is illustrated in the accompanying drawing, in which:

Fig. 1 shows a hold-ing device for knife blades .in side view,

Fig. 2 :shows the device partly in section, with a knife 'blade mounted in it,

Fig. 3 is a section on the line A-'B of Fig. 2,

Fig. 4 shows a knife blade which has been treated in accordance with prior methods, showing the points at which it was held, and

Fig. 5 shows a knife blade which has been treated with the aid of a device according to the invention.

The device illustrated comprises essentially an elongated abutment 1, suited to the shape of the workpiece to be treated, whichis secured to .a holding arm 2. By means of this holding arm 2, which has a transverse bore 3, the abutment 1 can be adjus'tably, e. g. rotatably secured to a swinga'ble arm in different "angular positions, the swingable arm being swingably mounted on a stationary support outside the drum containing the treating medium, in such manner that'theabutment ltogether with the work-piece can be moved into or outof the interior of the'drum.

The abutment 1, or at least the supporting surface 4 thereof, has a concavity which is so shaped that a knife 'blade becomes correspondingly resiliently deformed and applies itself accurately and without play to the surface 4, when it is pressed with suflicient pressure against the abutment by the application of force to the side of the head 6 of the blade.- This effect is achieved by means =of'a tool arranged at the rear end of the abutment 1, the tool being capable of receiving the tang 7 of the knife blade 5 and of exerting thereon a force which pressesthe blade, with resilient deformation, into the concavity of the abutment surface 4.

In the example illustrated, which is particularlyad vantageous, the rear end "of the abutment-1 is forked to provide two eyes 8 between which an "eccentric roller 10 is rotatably mounted on a screw-threaded-bol-t 9 which projects through the eyes-8. 'The roller 10-isfixedto the bolt '9 by -a pin'll. Theb'olt 9 can,--by meansof its'screw head 12, be turned together with the eccentricroller 10 and tightened. The eccentric roller-10 has a peripheral, semi-circular groove 13 which is formed with transverse knurling as can be seen in the sectional view, Fig. 2. The annular groove 13 is of such size that the round tang 7 of the knife blade 5 can engage in the groove and contact the knurling therein.

Adjacent the eccentric roller 10 is arranged an abutlar cross-section, for receiving the upper part of the tang 7.

For the purpose of mounting a knife blade 5, the tang 7 is inserted between the eccentric roller 10 and the abutment member 14 into the annular groove 13 and the longitudinal groove 16, and then the eccentric roller 10 is turned by means of the bolt head 12 in the direction of the arrow 17 (Fig. 2). The eccentric roller is thereby caused to press the tang 7 firmly against the lower surface of the member 14, in the groove 16. The lower surface of the member now extends so that the knife blade 5, if the concave surface 4 were not provided, would project without bending in a plane containing the axis 18 (Fig. 2). As a result of the curvature of the surface 4, however, when the rear end of the tang 7 is pressed against the abutment member 14 the knife blade must bend resiliently so that it follows the corresponding shaped curvature of the surface 4 and applies itself thereto, as shown in Fig. 2. The blade is thereby strongly stressed, so that it is held firmly on the abutment 1.

The eccentric roller also operates to draw the tang 7 rearwardly, due to the knurling of the annular groove 13, until the head 6 contacts the front end surfaces of the abutment member 14 and of the wall portion 21 of the device. Between these stop surfaces and the rearward limit of the surface 4, the abutment 1 is provided with a recess 19 which enables easy insertion of the tang 7 and head 6.

As Fig. 5 shows, a knife blade 5 held in accordance with the invention has on the treated surfaces, which are freely exposed during treatment, no blemishes such as those on the blade 5 which is shown by way of contrast in Fig. 4 and which has been held at the forward end also. The blade 5' has near its point, where it has been held during treatment, blemishes 20 which have to be dealt with in a subsequent operation with the blade held at other points.

By appropriate adjustment of the holding device according to the invention in the path of the rotating treating medium, and in some cases by an additional actual movement of the device in the medium, the angle necessary for the best possible treatment of the blade can be formed between the blade surface to be treated and the moving stream of treating medium, in that for example the holding arm 2 of the abutment 1 is correspondingly positioned or rotated on a Work-piece holder, advantageously on a swingable arm.

The holding device according to the invention is intended primarily for the treatment of knife blades in a centrifuge drum partly filled with grinding medium. However, it can also be constructed analogously for the finishing or polishing of similar articles.

I claim:

1. An apparatus for mounting knife blades for treatment such as grinding and polishing in a mass of treating material rotating in a centrifuge drum into which mass the knife blade to be treated is at least partially dipped, comprising a blade holder in the form of an elongated supporting surface member capable of supporting at least the major part of a knife blade on a surface thereof, the

supporting surface having a concave curvature extending in the longitudinal direction of the member and corresponding to a resiliently longitudinal deformed shape of the knife blade to be treated and having at its rear end a holding tool with an abutment member acting as a means for mounting a tang of the knife blade against the abutment member and thereby resiliently bending the knife blade and pressing it against the concave curvature of the supporting surface.

2. An apparatus as set forth in claim 1, in which the abutment member is arranged at an angle to the tangent of said concave curvature of the supporting surface, and in which the holding tool includes a rotatable eccentric mounted opposite to said abutment member and being selectively adjustable in a position in which said tang is capable to be inserted between the eccentric and the abut ment member and in a position in which said holding tool is pressed on rotation of the eccentric against the abutment member and the knife blade deformed to contact against the concave curvature of the supporting surface.

3. An apparatus as set forth in claim 1, in which the abutment member is arranged at an angle to the tangent of said concave curvature of the supporting surface, and in which the holding tool includes a rotatable eccentric mounted opposite to said abutment member and being selectively adjustable in a position in which said tang is capable to be inserted between the eccentric and the abutment member and in a position in which said holding tool is pressed on rotation of the eccentric against the abutment member and the knife blade deformed to contact against the concave curvature of the supporting surface, said eccentric being in the form of a roller mounted on a bolt in two spaced eyes formed at the rear end of said abutment member.

4. An apparatus as set forth in claim 1, in which the abutment member is arranged at an angle to the tangent of said concave curvature of the supporting surface, and in which the holding tool includes a rotatable eccentric mounted opposite to said abutment member and being selectively adjustable in a position in which said tang is capable to be inserted between the eccentric and the abutment member and in a position in which said holding tool is pressed on rotation of the eccentric against the abutment member and the knife blade deformed to contact against the concave curvature of the supporting surface, said eccentric being in the form of a roller mounted on a bolt in two spaced eyes formed at the rear end of said abutment member, said roller having an annular groove of substantially semi-circular cross section the surface of which is transversely knurled to receive a part of said tang, and said abutment member having a longitudinal groove opposite the annular groove of said eccentric roller for receiving a part of said tang.

References Cited in the file of this patent UNITED STATES PATENTS 81,608 Curtiss Sept. 1, 1868 191,811 Nicholson June 12, 1877 479,669 Shaw July 26, 1892 531,806 Te Paske Ian. 1, 1895 575,562 Block Jan. 19, 1897 891,177 Lamb June 16, 1908 1,178,827 Spellman Apr. 11, 1916 2,127,176 Kroecker Aug. 16, 1938 2,664,676 Cuppers Jan. 5, 1954 FOREIGN PATENTS 28,410 Switzerland June 4, 1903 174,203 Great Britain Jan. 23, 1922 

